title: Norovirus capsid proteins self-assemble through biphasic kinetics via long-lived stave-like intermediates.
abstract: The self-assembly kinetics for a norovirus capsid protein were probed by time-resolved small-angle X-ray scattering and then analyzed by singular value decomposition and global fitting. Only three species contribute to the total scattering intensities: dimers, intermediates comprising some 11 dimers, and icosahedral T = 3 capsids made up of 90 dimers. Three-dimensional reconstructions of the intermediate robustly show a stave-like shape consistent with an arrangement of two pentameric units connected by an interstitial dimer. Upon triggering of self-assembly, the biphasic kinetics consist of a fast step in which dimers are assembled into intermediates, followed by a slow step in which intermediates interlock into capsids. This simple kinetic model reproduces experimental data with an excellent agreement over 6 decades in time and with nanometer resolution. The extracted form factors are robust against changes in experimental conditions. These findings challenge and complement currently accepted models for the assembly of norovirus capsids.
authors.affiliation: Laboratoire de Physique des Solides, Université Paris-Sud , CNRS, 91405 Orsay, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Tresset
authors.forename: Clémence
authors.initials: C
authors.lastname: Le Coeur
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Bryche
authors.forename: Mouna
authors.initials: M
authors.lastname: Tatou
authors.forename: Mehdi
authors.initials: M
authors.lastname: Zeghal
authors.forename: Annie
authors.initials: A
authors.lastname: Charpilienne
authors.forename: Didier
authors.initials: D
authors.lastname: Poncet
authors.forename: Doru
authors.initials: D
authors.lastname: Constantin
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bressanelli
mesh_terms: D036022:Capsid Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D029322:Norovirus / Q000737:chemistry*; D011789:Quantum Theory; D053838:Scattering, Small Angle; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D036022:Capsid Proteins